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Lignin is the most abundant renewable aromatic resource on the planet, and it may be exploited to make the controlled release fertilizers (CRFs) that aid in human sustainable agriculture. Many researches on lignin-based CRFs have been conducted in recent years because of their exceptional controlled-release qualities. Lignin-based physically impeded CRFs can be produced by absorbing or wrapping nutrients and act as a longtime nutrient carrier, while chemically modified and chelated CRFs are produced by changing lignin structure to produce more active site and interaction between lignin and nutrients. In this review, lignin is evaluated on the basis of the manufacturing of various types of CRFs. The processes of lignin-based coated, chemically modified and chelated CRFs as well as lignin hydrogel-based CRFs are systematically summarized. Moreover, the general mechanism for controlled release of lignin-based CRFs is discussed. Finally, three common evaluation criteria of lignin-based CRFs efficiency are proposed. Overall, the use of lignin-based CRFs has the potential to greatly enhance resource efficiency and environmental protection.

Drought is one of the major agricultural problems which cause losses to crop productivity. It is a worldwide problem and prevails in many parts of the world as a major threat to agriculture. Potassium (K) is considered to be an essential nutrient that plays an important role in growth, development and defense response in the plant under stressful conditions. This work investigated the effects of K in drought tolerance of chickpea seedlings by examining growth, photosynthetic performance, total osmo-regulation substance contents and antioxidative enzymes subjected to drought stress. The drought stress impaired the growth (root and shoot dry weight, root: shoot ratio, seedlings biomass), water relations, photosynthetic attributes, transpiration rate and chlorophyll contents and anti-oxidants activity of chickpea seedlings. Nonetheless, the foliar application K improved the growth, water relations, photosynthetic attributes, transpiration rate, chlorophyll contents and anti-oxidative activity of chickpea under drought conditions. Moreover, an increase in antioxidant enzyme activity and accumulation of osmoprotectants (proline, soluble protein and soluble sugar) was noted under stressed conditions, which was more pronounced in chickpea which experienced of K application. To conclude that, foliar application of K mitigated the adverse effect of drought, K was proved to be even more effective in alleviating the adverse effect of drought stress on chickpea.

Lithium (Li) is gaining attention due to rapid rise in modern industries but their ultimate fingerprints on plants are not well established. Herein, we executed a meta-analysis of the existing recent literature investigating the impact of Li sources and levels on plant species under different growth conditions to understand the existing state of knowledge. Toxic effects of Li exposure in plants varies as a function of medium and interestingly, more negative responses are reported in hydroponic media as compared to soil and foliar application. Additionally, toxic effects of Li vary with Li source materials and LiCl more negatively affected plant development parameters such as plant germination (n = 48) and root biomass (n = 57) and recorded highly uptake in plants (n = 78), while LiNO

In the present study, we investigated the impact of different combinations of wheat straw biochar, compost and biogas slurry on maize growth, physiology, and nutritional status in less productive soils. The experiment was performed as a completely randomized block design in a greenhouse pot experiment. The compost and biogas slurry were applied with and without biochar. The results revealed that a combination of biochar, compost, and biogas slurry enhanced the cation exchange capacity (31%), carbon (83%), phosphorus (67%) and potassium (81%) contents in the soil. Likewise, a significant increase in soil microbial biomass carbon (15%) and nitrogen (37%) was noticed with the combined use of all organic amendments. Moreover, the combined application of biochar, compost and biogas slurry enhanced soil urease and &beta, glucosidase activity up to 96% and 67% over control respectively. In addition, plant height, chlorophyll content, water use efficiency and 1000-grain weight were also enhanced up to 54%, 90%, 53% and 21% respectively, with the combined use of all amendments. Here, biochar addition helped to reduce the nutrient losses of compost and biogas slurry as well. It is concluded that biochar application in combination with compost and biogas slurry could be a more sustainable, environment-friendly and cost-effective approach, particularly for less fertile soils.

Environmental pollution by heavy metals (HMs) has raised considerable attention due to their toxic impacts on plants, animals and human beings. Thus, the environmental cleanup of these toxic (HMs) is extremely urgent both from the environmental and biological point of view. To remediate HMs-polluted environment, several nanoparticles (NPs) such as metals and its oxides, carbon materials, zeolites, and bimetallic NPs have been documented. Among these, Fe-based NPs have emerged as an effective choice for remediating environmental contamination, due to infinite size, high reactivity, and adsorption properties. This review summarizes the utilization of various Fe-based NPs such as nano zero-valent iron (NZVI), modified-NZVI, supported-NZVI, doped-NZVI, and Fe oxides and hydroxides in remediating the HMs-polluted environment. It presents a comprehensive elaboration on the possible reaction mechanisms between the Fe-based NPs and heavy metals, including adsorption, oxidation/reduction, and precipitation. Subsequently, the environmental factors (e.g., pH, organic matter, and redox) affecting the reactivity of the Fe-based NPs with heavy metals are also highlighted in the current study. Research shows that Fe-based NPs can be toxic to living organisms. In this context, this review points out the environmental hazards associated with the application of Fe-based NPs and proposes future recommendations for the utilization of these NPs.

Chromium (Cr) contamination in farmlands has become a serious environmental concern due to the excessive use of industrial wastewater as an irrigation source. Therefore, some important measures need to be taken for reducing its mobility in a soil profile. A pot study was conducted to evaluate the effectiveness of sugarcane bagasse derived biochar and acidified manure on Cr mobility and its uptake by maize plant. Results showed that the application of biochar and acidified manure significantly changed soil pH, improved crop growth and as well as reduce the antioxidant response of maize in Cr contaminated soil. The concentration of bioavailable (AB-DTPA) extractable Cr in soil decreased with the addition of co-use of biochar (3%) and acidified manure (5%) by 36% relative to control. The maximum reduction in superoxidase dismutase (SOD), peroxidase dismutase (POD), and catalase activity assay (CAT), and ascorbate peroxidase activity (APX) was occurred by 41%, 51%, 20%, and 55%, respectively when biochar (3%) amended with the combination of acidified manure in Cr contaminated soil. Among all the amendments, biochar at 3% application combination with acidified manure (B2 + AMS) offered significantly minimize Cr mobility (Cr-III (44%) and Cr-VI (22%)) and thereby reduce its uptake by maize plant.